JP2004197735A - Reversible automatic fan control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reversible automatic fan control system for a radiator. <P>SOLUTION: A method of operating the fan control system associated with the radiator may include a step of rotating a fan in a first direction at an operating speed to direct cool air toward the radiator for a first preset period. After expiration of the first preset period, rotation of the fan in the first direction may be decelerated. The method may also include a step of accelerating the fan in a second direction opposite to the first direction and a step of rotating the fan at a predetermined speed in the second direction for a second preset period. After expiration of the second preset period, the rotation of the fan may be in the second direction decelerated and the fan may then be accelerated in the first direction to the operating speed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates generally to a reversible fan associated with a radiator of a machine, and more particularly to a reversible automatic fan control system and process.

  Many types of machines that use a motive engine also include a radiator to supply the engine with coolant, such as water, antifreeze, etc., to ensure that the engine does not overheat. The radiator is generally associated with a fan that supplies cooling air to the radiator. The radiator is usually located in front of the fan, and the fan usually draws air through the radiator to cool the liquid coolant for the engine.

  In many types of applications, machines operate or move in dirty and / or debris-rich environments. As a result, debris, such as dirt, insects, debris, etc., will remain on the radiator as the fan draws air into the machine through the radiator. Therefore, debris contained in the air passing through the radiator may remain in the radiator, and often actually remains in the radiator.

  In some machines, hydraulic circuits, electrical circuits, etc. may be used to selectively switch the operating mode of the cooling fan so that the cooling fan can be stopped, rotated forward, or reversed. For example, U.S. Pat. No. 6,037,045 to Yamagishi discloses a control device that can be used to reverse a cooling fan based on coolant temperature. In particular, the control device reverses the cooling fan when the temperature of the coolant is higher than a predetermined temperature, while the temperature of the hydraulic oil is lower than the predetermined temperature. This causes a backflow of air, releasing debris that remains in the radiator.

U.S. Pat. No. 6,076,488

  However, in this operation, the control device only reverses the cooling fan when the temperature of the cooling water is higher than the predetermined temperature of the hydraulic oil. Although reversing the fan can release debris that remains in the radiator, this operation does not allow for automatic regular intervals to reverse the fan to remove radiator debris.

  According to an exemplary aspect of the present invention, a method of operating a fan control system associated with a radiator includes rotating a fan at a certain operating speed in a first direction to generate air during a first predetermined time period. The method may include a step of directing the radiator toward the radiator and a step of reducing the rotation of the fan in the first direction after the first predetermined period ends. The method also includes accelerating rotation of the fan in a second direction opposite to the first direction to a predetermined speed, and causing the fan to move in the second direction at a predetermined speed during a second predetermined period. The method may include the step of rotating and the step of reducing the rotation of the fan in the second direction after the end of the second predetermined period. The method may further include accelerating the rotation of the fan in the first direction to an operating speed.

  It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

  The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the description, are used to explain the principles of the invention.

  Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

  FIG. 1 is a schematic diagram of a reversible automatic fan control system 10 according to an exemplary embodiment of the present invention. A radiator 12, located separately from the fan control system 10, provides a coolant such as water, antifreeze, etc. for the engine (not shown) or other equipment of the machine (not shown) that needs to be cooled during operation. Is generally provided for cooling. The fan control system 10 may include a cooling fan 14 and a working fluid cooler 16. A hydraulic fluid cooler 16 is generally provided for cooling hydraulic fluid, such as oil, for operating hydraulic equipment of the machine. By arranging the cooling fans 14, it is possible to perform forced cooling to the radiator 12 and the working fluid cooler 16.

  For example, when the cooling fan 14 is driven in the first direction, the cooling fan 14 is passed through the air passage 18 so that the airflow from the cooling fan 14 passes through the radiator 12 and the hydraulic fluid cooler 16 in the forward direction 46. Can be arranged. Conversely, when the cooling fan 14 is rotated in a second direction opposite to the first direction, air flows in a reverse direction 48 from the radiator 12 and the cooler 16 toward the cooling fan 14. The cooling fan 14 can be stopped, driven to a first forward rotation, or driven to a second reverse rotation.

  Fan control system 10 may include a source of pressurized fluid (eg, pressure-sensitive variable displacement hydraulic pump 20), a fluid-operated motor (eg, reversible hydraulic motor 26), and a fluid reservoir or tank 44. Motor 26 may include a first port 26a and a second port 26b. The fan control system 10 also includes a first valve (eg, a directional control valve 36) that can reverse the rotation of the fan 14 by selectively directing pressurized fluid from the pump 20 to the first port 26a or the second port 26b. ). In an exemplary embodiment, first valve 36 may be a solenoid operated directional control valve. Fan control system 10 may also include a second valve (eg, variable control valve 60) that can increase or decrease the rotational speed of cooling fan 14 in either direction. The variable control valve 60 may be, for example, a pressure reducing valve that operates to supply a pressure signal to the pump 20 to increase or decrease the rotational speed of the cooling fan 14 as desired.

  The pump 20 may be adapted to be rotated by, for example, a motor of an engine (not shown). Pump 20 is fluidly connected to reservoir 44 via hydraulic line 22 so that hydraulic fluid can be supplied from reservoir 44 to pump 20. Pump 20 is also fluidly connected to directional control valve 36 and variable control valve 60 via hydraulic line 24 so that hydraulic fluid can be supplied from fluid pump 20 to valves 36, 60.

  Pump 20 may supply fluid to first port 26 a of motor 26 through directional control valve 36 and via hydraulic line 28. The pump 20 may supply fluid to the second port 26 b of the motor 26 through the directional control valve 36 and via the hydraulic line 29. In one exemplary embodiment, hydraulic circuit 10 may include two relief valves 32, 34 located on hydraulic lines 30a, 30b, respectively. The hydraulic lines 30a, 30b are fluidly connected to the hydraulic lines 28, 29. If the fluid pressure is too great that the motor 26 can be damaged, depending on the position of the directional control valve 36, hydraulic fluid will bypass the motor 26 by appropriate relief valves 32, 34 and the individual hydraulic lines It is possible to move through 30a, 30b.

  The direction control valve 36 can control the rotation direction of the motor 26. As described above, the directional control valve 36 can be located in the fan control system 10 between the pump 20 and the motor 26. The direction control valve 36 includes, for example, a neutral position N for stopping the fan, a front position F for rotating the fan in a first forward direction, and a reverse position for rotating the fan in a second reverse direction. It may be a 3 position 4 port valve with R. Therefore, the direction control valve 36 can stop the motor 26, rotate the motor 26 forward, or reverse the motor 26.

  The spool valve element of the directional control valve 36 (shown) according to the relationship between the biasing force of the return spring 40 and the opposing force generated by the solenoid 38 to stop the motor 26 or to rotate forward or reverse. Can move). For example, a voltage may be selectively applied electrically to the solenoid 38 to generate a counterforce acting in the opposite direction of the biasing force of the spring 40. Thereby, the direction control valve 36 can shut off or control the flow direction of the fluid sent from the pump 20 to the motor 26. When the directional control valve 36 is in the forward position F, the valve 36 directs pressurized fluid from the pump 20 via the hydraulic line 28 to the first port 26a of the motor 26. When the valve 36 is in the reverse position R, the valve 36 directs pressurized fluid from the pump 20 via the hydraulic line 29 to the second port 26b of the motor 26.

  Controller 50 can be associated with directional control valve 36. The controller 50 can be adapted to automatically shift the position of the directional control valve 36 to and from the neutral position N, forward position F and reverse position R. Controller 50 may include a controller 52 electrically connected to solenoid 38 of directional control valve 36.

  In one embodiment, manual switch 54 can be associated with controller 50. The manual switch 54 stops the automatic control of the directional control valve 36 to enable manual control. Thus, the cooling fan 14 can be reversed by manually shifting the directional control valve 36 to the reverse position R.

  Variable control valve 60 can be provided to change the fluid pressure signal communicated to pump 20. Next, by changing the fluid output signal supplied to the pump 20, the fluid output from the pump 20 supplied to the motor 26 through the directional control valve 36 is changed. By changing the amount of fluid to the motor 26, the rotation of the motor 26 is increased or decreased, which in turn causes the rotational speed of the cooling fan 14 to be increased or decreased, respectively. An increase or decrease in the rotational speed of the cooling fan 14 can occur in both a first forward direction and a second reverse direction.

  The output of variable control valve 60 may be fluidly connected to pump 20 via hydraulic line 76 to variably provide a fluid pressure signal to pump 20. The valve 60 may be connected to the reservoir 44 via hydraulic lines 66 and 68 so that hydraulic fluid can also be drained from the valve 60 to the reservoir 44. Valve 60 may also include a solenoid 62 and a spring 64. A controller 70 can be provided to control the valve 60 to change the fluid pressure signal to the pump 20. Controller 70 may include a controller 72 and a manual switch 74. An output terminal of controller 70 may be electrically connected to solenoid 62 of variable control valve 60. In conjunction with a computer algorithm, the controller 70 can change the current supplied to the solenoid 62 to change the fluid pressure signal to the pump 20, which in turn causes the fluid from the pump 20 to change. You can change the output.

  System 10 may include a main controller 80 configured to analyze system parameters and / or send instructions to controllers 50, 70. It should be understood that the controller 80 and the controllers 50, 70 can be combined. It should also be understood that controller 80 may be or interface with a computer.

  Referring to FIG. 2, an exemplary embodiment of a reversible automatic fan control process 100 according to the present invention is described. In step 110, the machine's engine (not shown) is started after the machine is turned on. During the exemplary process 100, the machine may be shut down or may be moving. If shut down, the machine may be in work operation.

In step 120, after the engine is started, the cooling fan 14 may rotate in a first direction normal operating speed V _N. The first direction may be, for example, a direction that generates an airflow in a forward direction 46, that is, a direction that supplies cooling air to the radiator 12. While rotating in a first direction, cooling fan 14 may supply cooling air to radiator 12. The controller 80 may rotate the fan 14 in a normal operating speed V _N by directing normal operating current I _N to the solenoid 62 of the variable valve 60. Operating speed V _N of the normal is any speed not exceeding the maximum rotational speed V _MAX of the fan 14, it may be determined in accordance with the fan control system for maintaining the temperature of the radiator 12 to a desired operating range. The maximum rotational speed V _MAX may be determined by mechanical and hydraulic limits of the fan 14. Control continues to step 130.

  Next, at step 130, the controller 80 determines whether the first predetermined period A or the normal operation period has elapsed. If period A has elapsed, control continues to step 140. Otherwise, if period A has not elapsed, control returns to step 130.

If the controller 80 determines in step 140 that the period A has elapsed, the rotation of the cooling fan 14 in the first direction will cause the current to flow to the solenoid 62 of the variable control valve 60 at a first predetermined ramp rate. It is slowed down by increasing. The first ramp rate, while maintaining hydraulic and mechanical stability of the fan control system 10, are selected as much as possible to the appropriate reverse speed V _R to reach quickly. Similarly, suitable reverse speed V _R, while maintaining hydraulic and mechanical stability of the fan control system 10, is selected the time period used in the reverse of the cooling fan 14 so as to minimize. For example, slowing the fan 14 to a standstill before reversing may provide improved hydraulic and mechanical stability, but the time required to completely stop the fan requires the radiator 12 and the cooler 16 to operate. Undesirable temperatures can result. Therefore, when determining the appropriate reverse speed V _R, it is possible to perform a suitable compromise between the time used and the hydraulic and mechanical stability of the cooling fan 14, the reverse rotation of the cooling fan 14 . Control then continues to step 150.

  It should be understood that the ramp rate of the current to the solenoid 62 of the variable control valve 60 is inversely proportional to the acceleration of the cooling fan 14. That is, the cooling fan 14 is decelerated as the current to the solenoid 62 increases, and the cooling fan 14 is accelerated as the current to the solenoid 62 decreases. For example, when the amount of current to the solenoid 62 increases, the amount of fluid output from the pump 20 decreases. As the fluid output from pump 20 decreases, the rotational speed of motor 26 decreases, and then cooling fan 14 is decelerated. The converse is true when the current to the solenoid 62 decreases.

  It should also be understood that the rotational speed of the cooling fan 14 is inversely proportional to the current supplied to the solenoid 62 of the variable control valve 60. However, the rotational speed of the cooling fan 14 does not increase or decrease instantaneously as the current to the solenoid 62 increases or decreases because each of the cooling fan 14 and the motor 26 must overcome the momentum and acceleration that must be overcome during deceleration. It has a mass that provides a moment of inertia that must sometimes be overcome.

In step 150, the controller 80, the current sent to the solenoid 62 of the variable control valve 60 determines whether the reached reverse current I _R corresponding to the reverse rotation speed V _R of the cooling fan 14. If current sent to the solenoid 62 reaches the reverse current I _R, control continues to step 160. Otherwise, if the current sent to the solenoid 62 did not reach the reverse current I _R, the control returns to step 140.

In step 160, after the controller 80 has determined that the current sent to the solenoid 62 reaches the reverse current I _R, the controller 80 initiates a first predetermined delay period, the cooling fan 14 is reversed speed V _R To allow you to slow down. Next, in step 170, the controller 80 maintains the supply of the reverse current _{I R} to the solenoid. Control continues to step 180.

  Next, at step 180, the controller 80 determines whether the delay period has elapsed. If the delay period has elapsed, control continues to step 190. Otherwise, if the delay period has not elapsed, control returns to step 170.

  In step 190, when the controller 80 determines that the delay period has elapsed, the rotation direction of the cooling fan is reversed in a second direction opposite to the first direction. The second direction may be, for example, a direction that generates an airflow in a reverse direction 48, that is, a direction that draws air from the radiator 12. For example, the cooling fan 14 may reverse in a second direction when the controller 80 operates the solenoid 38 of the directional control valve 36 to move the valve 36 to its reverse position R. Control continues to step 200.

Next, in step 200, the rotational speed of the fan 14 in the second direction is accelerated at a second predetermined ramp speed by reducing the current to the solenoid 62 of the variable control valve 60. The second ramp speed may be selected to reach a predetermined reverse speed V _M (eg, maximum reverse speed) as quickly as possible while maintaining hydraulic and mechanical stability of the fan control system 10. Similarly, the predetermined reverse speed V _M, the cooling fan 14 may be selected to minimize the time period required to clean the debris from the radiator 12. In an embodiment, the predetermined reverse speed _{V M} may be up fan speed _{V MAX.} Control then continues to step 210.

In step 210, the controller 80, the current sent to the solenoid 62 of the variable control valve 60 determines whether it has reached the minimum current I _MIN corresponding to a predetermined reverse speed V _M of the cooling fan 14. If the current delivered to the solenoid 62 has reached the minimum current I _MIN , control continues to step 220. Otherwise, if the current delivered to solenoid 62 has not reached minimum current I _MIN , control returns to step 200.

Next, at step 220, after the controller 80 determines that the current sent to the solenoid 62 has reached the minimum current I _MIN , the controller 80 begins a second predetermined period or a reversal period. Next, at step 230, the controller 80 maintains the supply of the minimum current I _MIN to the solenoid. During the reversal period, the cooling fan 14 may rotate in the second direction at any speed that does not exceed the maximum rotation speed V _MAX of the cooling fan 14. Control continues to step 240.

  At step 240, controller 80 determines whether the reversal period has elapsed. If the reversal period has elapsed, control continues to step 250. Otherwise, if the reversal period has not elapsed, control returns to step 230.

If the controller 80 determines that the reversal period has elapsed at step 250, the rotation of the cooling fan 14 in the second direction will cause the current to flow to the solenoid 62 of the variable control valve 60 at a third predetermined ramp rate. It is slowed down by increasing. Third ramp rate, while maintaining hydraulic and mechanical stability of the fan control system 10 may be selected so as to reach as quickly as possible to the appropriate reverse speed V _R. Or it may reduce rotation speed of the cooling fan 14 to the different second appropriate reversing speed appropriate reverse speed V _R. Similarly, the second suitable reversing speed is selectably selected to minimize the time period used to reverse the cooling fan 14 while maintaining hydraulic and mechanical stability of the fan control system 10. Can be done. Control then continues to step 260.

Next, in step 260, the controller 80, the current sent to the solenoid 62 of the variable control valve 60 determines whether the reached reverse current I _R corresponding to the reverse rotation speed V _R of the cooling fan 14. If current sent to the solenoid 62 has reached the reverse current I _R, control continues to step 270. Otherwise, if the current sent to the solenoid 62 has not reached the reverse current I _R, the control returns to step 250.

In step 270, after the controller 80 has determined that the current sent to the solenoid 62 reaches the reverse current I _R, the controller 80 initiates a second predetermined delay period, the cooling fan 14 is reversed speed V _R To allow you to slow down. Next, in step 280, the controller 80 maintains the supply of the reverse current _{I R} to the solenoid. Control continues to step 290.

  Next, at step 290, controller 80 determines whether a second delay period has elapsed. If the second delay period has elapsed, control continues to step 300. Otherwise, if the second delay period has not elapsed, control returns to step 280.

  If the controller 80 determines in step 300 that the second delay period has elapsed, the rotation direction of the cooling fan is reversed in the first direction and returns. Control then continues to step 310.

Next, in step 310, the rotational speed of the fan 14 in the first direction is accelerated at a fourth predetermined ramp speed by reducing the current to the solenoid 62 of the variable control valve 60. Fourth ramp rate, while maintaining hydraulic and mechanical stability of the fan control system 10 may be selected so as to reach as quickly as possible to the normal operating speed V _N. Control then continues to step 320.

In step 320, the controller 80, the current sent to the solenoid 62 of the variable control valve 60 determines whether the reached normal operating current I _N corresponding to the operating speed V _N of the normal of the cooling fan 14. If current sent to the solenoid 62 has reached the normal operating current I _N, control continues to step 330. Otherwise, if the current sent to the solenoid 62 has not reached the normal operating current I _N, the control returns to step 310.

In step 330, after the controller 80 has determined that the current sent to the solenoid 62 reaches a normal operating current I _N, the controller 80 starts the operation period A predetermined normal and control continues to step 340 . Next, at step 340, control is returned to step 120.

  Generally, a computer (not shown) can be provided in association with the machine. The computer may include one or more parameters including certain parameters of the control process 100, such as a predetermined normal operating period A, a predetermined delay time, a predetermined reversal period, one or more predetermined ramp speeds, and a predetermined current. Algorithm. In an alternative embodiment, these parameters may be input to the algorithm by the machine operator. A timing device (not shown) monitors the elapsed time in connection with the control process 100 in association with an algorithm contained in the computer.

  In an exemplary embodiment, the computer may include a demand fan algorithm and a reversing fan algorithm, both of which are utilized to control the direction and speed of rotation of the cooling fan. The computer may use the demand fan algorithm during normal operation of the machine. After time A has elapsed, the computer switches to the reversing fan algorithm, slows down the fan, reverses the fan during time period C, slows down the fan again, and restarts the cooling fan again. Reverse and return to normal rotation. The computer can switch back to the request fan algorithm during time period A as the cooling fan rotates in the forward direction.

  FIG. 3 is a graph showing the current flowing to the solenoid 62 of the variable control valve 60 during the control process 100 versus time. This graph includes periods of normal rotation (periods A and B) and reverse rotation (periods C and D).

Next, referring to FIGS. 1 and 2, the operation of the reversible fan control system 10 will be described in detail below. In general, “normal” operation of the machine involves rotating the cooling fan 14 to generate an airflow in the forward direction 46. In one exemplary embodiment, this may be achieved by using a demand fan algorithm. To rotate the fan 14 in the forward direction, the directional control solenoid valve 36 is in its forward position F. During the "regular" operating period A of FIG. 3, the current to the variable control valve 60 is a substantially constant "regular" current _IN , so that the fan 14 generally rotates at a substantially constant speed. Current I _N of the normal fan speed and normalized it should be understood that may vary with the machine.

  It should also be understood that the predetermined period A during which the cooling fan 14 rotates forward at a regular speed varies by machine. For example, period A can range from about 0 minutes to about 240 minutes. For example, in one exemplary embodiment, period A can be about 20 minutes. In another exemplary embodiment, period A can be about 30 minutes. Period A is the time during which a certain amount of debris is expected to remain in radiator 12 so that it may be necessary, beneficial, and / or efficient to rotate cooling fan 14 in the reverse direction to remove debris. It can represent a time period.

Cooling fan 14 may be rotated to generate airflow in forward direction 46 until controller 80 determines that period A has passed. After the time period A has passed, the controller 80 sends a signal to reduce the rotational speed of the fan in the forward direction. To achieve the desired rotational deceleration of the fan from the normal speed to the appropriate reversing speed, the controller 80 sends a signal to the controller 70 at a first predetermined ramp rate to the variable control valve 60. the current from the normal current I _N can increase the reverse current I _R.

Reverse current I _R is to be understood that may vary depending on the machine. For example, the reverse current _{I R} can be in the range of about 0.0 amps to about 5.0 amps. In the exemplary embodiment, the reverse current I _R may be about 1.5 amps. In another exemplary embodiment, the reverse current I _R may be about 1.8 amps. Or the reverse current I _R may be a parameter of the reverse algorithm, or can be entered by the machine operator.

Cooling fan 14 is decelerated from a normal operating speed over a period of time B V _N in the reverse rotation speed V _R. During the period B, the electric current to the solenoid 62 is gradually reduced in the reverse current I _R, also the first delay period elapses. Period B can vary with the machine. For example, period B may range from about 0 seconds to about 30 seconds. In an exemplary embodiment, period B may be about 2 seconds. In another exemplary embodiment, period B may be about 5 seconds.

After cooling fan 14 is decelerated in the reverse rotation speed V _R, the controller 80 sends a signal to the controller 50, operates the directional control valve 36, can shift the position of the directional control valve 36 to the reverse position R . As a result, the rotation direction of the cooling fan 14 is reversed, and an air flow is generated in the reverse direction 48.

After the direction of rotation of the cooling fan 14 is reversed, the controller 80 may send a signal to accelerate the rotation of the cooling fan 14 in the opposite direction. To achieve the desired rotational acceleration from the appropriate reverse speed to a predetermined speed (eg, maximum speed), controller 80 sends a signal to controller 70 to control the variable control valve at a second predetermined ramp speed. It may decrease the minimum current _{I MIN} current to 60 from reversing trip point current _{I R.}

It should be understood that the minimum current I _MIN can vary from machine to machine. For example, the minimum current I _MIN may be about 0.4 amps. The second ramp speed may also vary from machine to machine. For example, the current may be ramped down at a rate ranging from about 0.0 amps / sec to about 2.5 amps / sec. In an exemplary embodiment, the second ramp rate can be about 1 amp / sec.

When the current to the fan reaches the minimum current I _MIN, the rotation speed of the cooling fan 14 will soon reach a predetermined reverse speed V _M. Predetermined reverse speed _{V M} may be fast, for example at the maximum rotational speed _{V MAX} of the cooling fan 14. The controller 80 may rotate the cooling fan 14 in the reverse direction during a predetermined reverse rotation period. Time period C is to increase the speed of the reverse rotation speed V cooling from _R to a predetermined reverse speed V _M fan 14, and represents the time it takes to remove the debris from the radiator 12. Period C can vary from machine to machine. For example, time period C can range from about 0 seconds to about 120 seconds. In an exemplary embodiment, time period C can be about 20 seconds. In another exemplary embodiment, time period C can be about 30 seconds.

If the controller 80 determines that the reversal period has expired, the controller 80 may send a signal to slow down the rotation of the cooling fan 14 in the reverse direction. To achieve the desired rotational deceleration from a predetermined speed (e.g., maximum speed) to an appropriate reverse speed, controller 80 sends a signal to controller 70 to control the variable control valve at a third predetermined ramp speed. current to 60 from the minimum current _{I MIN} can increase the reverse current _{I R.}

Cooling fan 14 is decelerated from reverse over a period of time D predetermined speed V _M in the reverse rotation speed V _R. During the period D, the electric current to the solenoid 62 is gradually reduced in the reverse current I _R, also a second predetermined delay period elapses. The period D can be changed by a machine. For example, period D can range from about 0 seconds to about 30 seconds. In an exemplary embodiment, time period D may be about 2 seconds. In another exemplary embodiment, period D can be about 5 seconds.

When the cooling fan 14 is decelerated in the reverse rotation speed V _R, the controller 80 sends a signal to the controller 50, operates the directional control valve 36, may return to shift the position of the valve 36 to its forward position F . As a result, the rotation direction of the cooling fan 14 is reversed and returned, thereby generating an airflow of the normal rotation 46.

After the rotation of the cooling fan 14 is reversed to generate the airflow of the forward rotation 46, the controller 80 may send a signal to accelerate the rotation of the cooling fan 14. To achieve the desired rotational acceleration from the reverse speed to the normal speed, the controller 80 sends a signal to the controller 70 to reverse the current to the variable control valve 60 at a fourth predetermined ramp speed. It may decrease to the normal current _{I N} from the point current _{I R.}

  In one embodiment, the controller 80 sends a signal to direct the current to the variable control valve 60 to the same variable control valve 60 that was flowing to the variable control valve 60 before the controller 80 started the automatic reversal procedure using the reversing fan algorithm. The current can be reduced. In an exemplary embodiment, the controller 80 may store a value for the current to the valve 60 at a time immediately before it initiates an automatic reversal of rotation in the direction of the cooling fan 14. After the rotation in the direction of cooling fan 14 is reversed and returned in the forward direction, controller 80 may reduce the current to valve 60 to a stored current value.

  As described above, when the cooling fan 14 is reversed, debris remaining in the radiator 12 and the cooler 16 can be removed by the backflow of the cooling air passing through the radiator 12 and the cooler 16. Using the method described above, the air flowing in the reverse direction 48 may automatically clean the clogged portions of the radiator 12 and cooler 16 for a regular period of time.

  Further, the machine operator may manually remove debris by manually changing the rotation of the cooling fan 14 in the opposite direction. This occurs when the operator actuates the manual switch 54 to manually shift the directional control valve 36 to its reverse position R. Thus, in addition to automatic cleaning, cleaning of the plugged portion of the radiator 12 can be performed whenever the situation requires such manual cleaning. The manual reversal of the cooling fan may or may not restart period A for the timing of the automatic reversal. Further, the machine shutdown may or may not restart period A due to the automatic reversal timing.

  As shown in FIG. 1, the operation of the exemplary embodiment of the present invention can be performed by one or more controllers 80. The controller 80 includes a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an ASIC or other integrated circuit, and hardware electronics such as separate element circuits. It may include circuits or logic circuits and programmable logic devices such as PLDs, PLAs, FPGAs or PALs. In general, a finite state machine capable of implementing the flowchart shown in FIG. 2 can use any device to implement the functions of the controller of the present invention.

  It will be apparent to those skilled in the art that various modifications and variations can be made in the fan control system without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.

1 is a schematic diagram of an exemplary reversible automatic fan control system according to one embodiment of the present invention. 4 is a flowchart of an exemplary reversible automatic fan control process according to one embodiment of the present invention. 3 is a graph showing current versus time for the exemplary reversible automatic fan control process of FIG.

Explanation of reference numerals

Reference Signs List 10 hydraulic circuit 12 radiator 14 fan 16 hydraulic fluid (oil) cooler 18 air passage 20 hydraulic pump 22 hydraulic line 24 hydraulic line 26 motor 26a first port 26b of motor 26 second port 28b of motor 26 hydraulic line 29 hydraulic Line 30a Hydraulic line 30b Hydraulic line 32 Relief valve 34 Relief valve 36 First valve (directional control valve)
38 solenoid of valve 36 40 return spring of valve 36 44 tank 46 forward direction of air flow 48 reverse direction of air flow 50 controller 52 controller 54 manual switch 60 second valve (variable control valve)
62 Solenoid of valve 60 64 Spring of valve 60 66 Hydraulic line 68 Hydraulic line 70 Controller 72 Controller 74 Manual switch 76 Hydraulic line 80 Controller 100 Reversible automatic fan control process 110 Step: Start engine 120 Step: Start fan at operating speed 130 Decision: Did the predetermined operation period elapse?
140 step: deceleration of the fan 150 decision: current to the solenoid _{= I} R?
160 Step: a first delay period starts 170 Step: current to the solenoid = _{I R}
180 Decision: Has the delay period expired?
190 Step: Reverse direction of fan 200 Step: Accelerate fan in second direction 210 Decision: Current to solenoid = I _M ?
220 step: start of reversal period 230 step: current to solenoid = I _M
240 Decision: Has the reversal period expired?
250 Step: Deceleration of fan 260 Decision: Current to solenoid = I _R ?
270 Step: start 280 steps of a second delay period: current to the solenoid = _{I R}
290 Decision: Has the delay period expired?
300 Step: Reversing the direction of the fan 310 Step: Accelerating the fan in the first direction 320 Decision: Current to solenoid = I _N ?
330 step: start of predetermined operation period 340 step: return to step 120

Claims (10)

A method of operating a fan control system associated with a radiator, comprising:
Rotating the fan at a certain operating speed in a first direction to direct air toward the radiator during a first predetermined period;
Reducing the rotation of the fan in the first direction after the end of the first predetermined period;
Accelerating the rotation of the fan in a second direction opposite to the first direction to a predetermined speed;
Rotating the fan in a second direction at a predetermined speed during a second predetermined period;
Reducing the rotation of the fan in the second direction after the end of the second predetermined period;
Accelerating the rotation of the fan in the first direction to an operating speed.   The step of rotating the fan in a first direction includes supplying pressurized fluid to a first port of a motor connected to the fan, and the step of rotating the fan in a second direction comprises the step of: The method of claim 1, comprising supplying fluid to a second port of a motor, wherein the predetermined speed is a maximum speed.   3. The method of claim 2, further comprising increasing a current to the solenoid valve, wherein the solenoid valve is configured to provide a pressure input to the pressure-sensitive pump that reduces the output of the pressure-sensitive pump and reduces the rotation of the fan. The method described in.   The method of claim 1, further comprising selectively supplying pressurized fluid to one of a first port of the motor and a second port of the motor to rotate the fan in one of a first direction and a second direction. 2. The method according to 1. A machine,
Radiator and
A fan associated with the radiator, wherein the fan directs air toward the radiator when the fan is rotated in a first direction, and the fan is rotated in a second direction opposite the first direction. A fan that is sometimes configured to draw air in the direction of the radiator,
At least one controller configured to cause the fan to rotate in a first direction at an operating speed during a first predetermined time period and to reduce the rotation of the fan after the first predetermined time period; The rotation of the fan in the second direction is accelerated to a predetermined speed, and the fan is rotated in the second direction at a predetermined speed during a second predetermined period. At least one controller further configured to reduce the rotation of the fan and further configured to accelerate the rotation of the fan in the first direction to an operating speed. A fluid operated motor coupled to the fan having a first port and a second port;
A first valve operable to selectively supply pressurized fluid to one of the first port and the second port to rotate the fan in one of the first direction and the second direction;
A second valve operable to alter the supply of pressurized fluid to a selected one of the first port and the second port;
A pump configured to supply pressurized fluid to the motor;
Further comprising
At least one controller supplies pressurized fluid to a first port to rotate the fan in a first direction, and supplies pressurized fluid to a second port to rotate the fan in a second direction. At least one controller is configured to operate a second valve to accelerate and decelerate the fan, and the predetermined speed is a maximum speed. The machine according to claim 5.   A first valve is arranged to direct pressurized fluid from the pump to a first port of the motor, and is arranged to direct pressurized fluid from the pump to a second port of the motor. The machine of claim 6, including a three position directional control valve having a configured second position.   The machine according to claim 7, wherein the pump is a variable displacement pressure-sensitive pump.   The machine according to claim 8, wherein the second valve is a variable control valve configured to supply a pressure signal to a variable displacement pressure sensitive pump. A controller is configured to supply current to the second valve, wherein the supply of pressurized fluid from the pump decreases when the current to the second valve is increased, and the current to the second valve decreases. 10. The machine of claim 9, wherein the supply of pressurized fluid from the pump increases when the pump is turned on.

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